What is the Galleri blood test?
Research in England and Wales is looking into a new blood test that could detect a range of cancers. Earlier research in America has been promising. But it needs further testing in larger trials.
A company called GRAIL Bio UK Ltd makes the Galleri blood test. It is not available in the UK outside of a clinical trial.
The NHS Galleri screening trial is looking at the test in people who do not have cancer. The SYMPLIFY study is looking at the Galleri test in people with possible cancer symptoms. Both the trial and study have now closed to recruitment.
What does the Galleri blood test look for?
The test looks for abnormal 
in the blood. The cells in our body release DNA that circulates in the blood. There are differences in the DNA of healthy cells and cancerous cells. The test aims to pick up these differences. Your blood is tested for signals that might mean you have cancer.
The researchers hope this test will pick up cancers at an early stage. Diagnosing cancer early means there is a greater chance of successful treatment.
The NHS Galleri screening trial
This trial is the result of a partnership between NHS England and a company called GRAIL. It has now closed to recruitment. The trial team used NHS records to search for people aged 50 to 77 who had:
- not been diagnosed with cancer in the last 3 years, or
- not been treated for cancer in the last 3 years
People in some parts of England received an invitation by letter to join. The trial team hoped to recruit 140,000 people.
Everyone taking part has 3 blood tests over the course of 2 years. This is a randomised trial. This means that those taking part are put into one of two groups by a computer:
- half the people have their samples tested using the Galleri test - this is the test group
- the other half don’t have the Galleri test and their blood samples will be stored and may be tested in the future - this is the control group
If you are in the test group and your result shows a cancer signal, this does not mean that you definitely have cancer. It means that you might have cancer. The trial team will explain your results. And refer you to a specialist doctor at your local hospital. You might have further tests.
What are the benefits and risks of taking part?
By taking part you could help others. The trial results may show that the Galleri test is able to pick up cancer early, when it is easier to treat. This in turn will help treat more cancers successfully.
The Galleri test is not perfect and can give a wrong result. This could cause you some anxiety. You may have tests that are unnecessary if it’s found you don't have cancer.
When you have your blood sample, a member of the trial team will explain the possible benefits and risks of taking part.
The SYMPLIFY study
This study is looking at the Galleri test in people with possible cancer symptoms. It has now closed to recruitment.
Everyone in the study had tests to check for cancer in the usual way. They also gave a sample of blood which was tested with the Galleri test.
The study team continue to follow those taking part. They will check health records. And they will collect information about appointments, tests and test results that people have.
Has it already been tested?
Researchers in America looked at an earlier version of the Galleri blood test. These trial results showed that the test was able to pick up over 50 types of cancer. This included those types of cancer that are difficult to diagnose early, such as pancreatic cancer and oesophageal cancer.
This was very early research in a small number of studies. The blood test now needs further testing in a larger number of people with both common and less common cancers. And research also needs to follow people for longer after the test.
We have more information about the Galleri blood test and the research so far in our press story.
I have symptoms of cancer, what should I do?
You should contact your doctor if:
- you have any possible signs and symptoms of cancer
- you notice a change that isn't normal for you
- you notice that a change continues or worsens even after you’ve sought help it
This should be the case, even if you are taking part in this research.
Your GP can refer you to a specialist or to have tests if they think that you might have possible symptoms of cancer.
Cancer screening
It’s very important that you consider cancer screening when invited, whether you are part of this research or not. This trial does not replace cancer screening. There are 3 national screening programmes in the UK:
Lung cancer screening is also recommended for people at high risk of developing lung cancer. This is called targeted lung cancer screening. It will be some time before a screening programme is rolled out across the UK. Meanwhile, there are lung health checks available in some parts of England.
Remember cancer screening is for people with no symptoms at all. If you have symptoms, don’t wait for a screening invitation. Contact your doctor as soon as possible.
